Telephone-service-observing system.



E. C. MOLINA.

TELEPHONE SERVICE osseavme SYSTEM.

APPLICATION FIILED DECJ. 1915.

1,245,490. Paben tedNov. 6, 1917.

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' Edward C Mal/ha ZW mam Patented Nov. 6, 1917.

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E. C. MOLINA.

TELEPHONE SERVICE OBSERVING SYSTEM. APPLlCATION FILED DEC. 1. 1915.

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unrrnn STATE EDWARD C. MOLINA, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

TELEPHONE-SERVICE-OBSERVING SYSTEM.

Specification of Letters Patent.

Patented Nov. 6, 191 7.

Application filed'December 1, 1915. Serial No. 64,489.

To all whom it may concern:

Be it known that I, EDWARD G. MOLINA, residing at East Orange, in the county of Essex and State of New Jersey have invented certain Improvements in 'lelephone- Service-Observing Systems, of which the following is a specification.

To determine the character of service being rendered telephone subscribers, 't is desirable that an observer situated, for example, at one oflice or central station of a multi-oifice district shall be informed as to the various details of the calls of groups of subscribers at the same or other oflices; such as the time at which a subscriber removes the receiver from its hook to initiate a call, the time of the operators response by plugging into the answering jack, the conversation between the subscriber and operator, the hanging up of the receiver at the substation and the withdrawal of the plug from the jack. All this should be accomplished for a considerable number of subscribers with the use of as few trunks as possible for connecting the lines under observation and the observers station. The present invention provides such information in a simple and effective manner, and with but one trunk for each observed group.

In the accompanying drawings, Figure 1 shows the equipment individual to two substation lines the service upon which is to be observed, this being according to a particular embodiment of the invention; while Fig. 2 illustrates the apparatus common to all the lines of the observed group and individual to the observing trunk.

As the equipment belonging to an bserved group of lines and the corresponding trunk is of the same character for all, that of but two lines of the group with their trunk is shown and will be described. These two substation lines L and L appear terminating at their respective answering jacks J and J at a central station A. Considering now the apparatus associated with the line L as typical of all the lines of the group, it has the usual line relay it and out relay R, the former controlling the line lamp At some convenient point, as the distributing frame, there may be temporarily connected to the substation line, as is indicated at the terminal 5, a service observing line provided with the initiating relays it? and R which, energized successively as .by the relays R R and R".

a result of the actuation of the line relay, start a train of operations leading to the connection of the line to the observing trunk if the latter is not already joined to a line of the group, or its being locked out therefrom if the trunk is busy. The energization of relay R may also be effected by an operators initiating relay R which is in parallel with the cut-ofl relay. When the secondary initiating relay R is energized in either of the ways mentioned, it causes the trunk-seizing relays .R R and R to become active, this bringing about the cooperation of the line and disengaged trunk. A sluggish lock-out relay B", when energized as a result of the trunk being in use, prevents this appropriation of the .trunk conductors of the various service observing lines of the group are multipled to the conductors of the service observing trunk, five of which conductors, L L L, 11 and L, lead through 'to the distant observing station, which may be at another office B. Of these trunk conductors, L and L are talking and the remainder controlling conductors. j

At the ofiice A, individual to the trunk and therefore common to the lines under observation, are a subscribers' relay R operated by current over the observed line when the receiver is removed from its hook, a trunk relay R which determines whether the trunk-seizing or lock-out relays shall receive current, an indication initiating relay R putting into effect the identification of the observed line, and indicator controller relays R and R. The last mentioned relays, acting in succession in consequence of the operation of relay R govern the holding magnet H, and through the stepping relay R the motor magnet M of an indicator controller S, which, as will later more clearly appear, controls the op eration of identifying the line under observation. This device S may consist of the wellknown step-bystep automatic selector, in which a brush 8 is moved by ratchet mechanism 8 over fixed contacts 8 under the influence of the motor magnet A pawl s actuated by the holding magnet H retains the brush in the position to which it is advanced, and when this pawl is wit drawn, a sprin a returns the brush ,to normal. A. test relay R responds through At t the are the brush 8 to an active condition of a particular terminal 8 and stops the advance of the operation by opening the stepping circuit. Associated with this end of the trunk is an observation limiting relay R the action of which, governed from the observers station, determines whether an originating call, or one beginning with the closure of the hook switch at asubstation, or a terminating call, started by insertion by the operator of the calling plug of a cord circuit in the jack of a called line, or both, shall be observed.

At the observing end of the trunk at --station 13 is a subscribers signal relay R and an operators signal relay R. The former under the influence of relays R and R and the latter governed by relay R control lamps or other signals Z and Z respectively showing by their illumination or non-illumination Whether the hook switch at the substation of the observed line is closed or open, and whether or not an operator has plugged into a jack of the line. ,There is also at the observing station an indicator S which may be practically identical with the controller S, except that in the present embodiment of the invention there is substituted for the brush .9 a pointer or indicating arm 8 movcorresponding to the like devices of the indicator controller, with relays R and R performing generally similar functions to the relays R and R. A suitable pulsator P furnishes the stepping impulses to both stepping relays. The observer is provided with two keys K and K. The former when actuated joins the observers receiving telephone to the line and controls certain relays of the indicating circuit and, through controller relays R and R over the trunk, the look-out relay R The key K when in its central position with the contacts open permits either an originating or a terminating Call to be observed. When upon its upper contact the observed cal-ls are limited to originating calls and when upon its lower contact to terminating.

Considering the operation of the system in detail and assuming the key K to be in its central position and a call to originate upon the substation line L, the closure of the line circuit at the substation incident tothe subscriber taking down the receiver causes the energization of the line relay R, which at its front contact supplies current to illuminate iine lamp Z and also gives a cirsuit in parallel therewith through the winding of primary initiating relay R and this in turn through its contact 10 completes a circuit through the lower winding of the secondary initiating relay R Further assuming that there is no line ofthis group under observation and that the resting contacts of the look-out relay R are therefore closed, there is a circuit from contact 11 of relay R through contact 12 of lock-out relay R and conductor 13 to the point 14, then in parallel through the windings of the trunk-seizing relays R and R to a point 15, on by way of contact 16 of relay R the lead 17 of the service observing line and through the back contact 18 of trunkrelay R The front contact 19 of relay R closes one break in the circuit of the look-out relay, whereby it would be operated in case the trunk were in use. This will more clearly appear later. The subscribers lamp Z at the observing station is now lighted as a consequence of the energization of relay R over the following circuitfront contact 10 of relay R conductor 20, front contact 21 of relay R lead 22, winding 23 ofthe trunk repeating coil I. trunk conductor L and winding of'relay R"; the attracted armature of "this subscribers relay supplying current to the lamp. The observer therefore is made aware that a call is awaiting observation upon the trunk and may depress her key K to unite her receiver to the talking conductors L and L at the contacts 24 and 25, and also making contacts 26 and 27 for purposes which will hereinafter be described.

By opening contact 28 relay R removes a short circuit 29 from the winding of relay R preparing it for operation. At front contact 30 of this relay a path for current to the operators signal relay R is made ready, awaiting the energization of the operators-relay R. Eontact 31 of relay R joins to the point 1 k in the parallel circuit of relays R and R a front contact of controller relay it, through which latter battery may be applied independently of the connection through contact 12 of the lockout relay R multaneously with relay B, it locked this pair of relays through contact 32, lead 33 and winding of trunk relay R independ- I ently of the path through the back contact of the last named relay. This lead 33 normally, or when the trunk is not in use, is extended by conductor 3i through the resting contacts 35 of all the relays R of the group in series, so that the relay R of any line of the group may, when the relays R of the associated lines are deenergized, complete at contact 32 the energizing circuit for trunk relay R Resting contact 36 of relay R in the path between the front contact of trunk relay R and the winding of lock-out relay R is opened, this not being used when the trunk is idle, and said relay it is joined at ercise its control. At contact 35 of relay R the connection between lead 33 and its extension 34-is broken, and there is substituted at front contact 39 a connection with a lead 40 extending to a contact 8 of the indicator controller S, said contact being individual to the line which has seized the trunk. Battery is thus applied through the winding of relay R to said contact.

When trunk relay R receives current through the locking circuit of relays R and- R, as already described, it operates and at its contact 41 completes a circuit through the winding of the indication initiating relay R and the normal colntact 42 of the indicator controller S. Relay R attracts its armatures and at contact 43 looks itself independently of the controller contact 42, which will be opened as soon as the controller begins its advance. At contact 44 there is now a circuit'by way of the winding of the primary controller relay R trunk conductor L contact 26 of key K,

closed by the observer after the subscribers lamp Z lighted, conductor 46, through the normal contact 47 of indicator S and the winding of the primary indicator relay R. The front contacts 48 and 49 of relays R and R thereupon cause the energization of the secondary indicator controller and indicater relays R and R respectively. Front contact 50 of relay R by short circuiting contact 47 provides for the continued energization of relay B after the indicator leaves its normal position. Contacts 51 and 52 of relays R and R close local circuits through resistances r and 1- for the holding magnets H and H, which apply the pawls s of the indicator controllerand indicator of the ratchet mechanism. There is also a circuit from the pulsator P at the observing station through front contact 53 of relay R indicator stepping relay R conductor 54, contact 27 of key K, trunk conductor L", controller stepping relay R back contact 56 of test relay R and front contact 55 of relay R The relays R and R responding to the impulses make and break the local circuits of the motor magnets M and M, so that the indicator controller and indicator move forward the brush .9 and pointer s in synchronism until the former touches the contact 8 belonging to the line which is connected with the trunk. Current thereupon flows through the winding of re lay R brush 8, contact 8 lead 40 of the service observing line, contact 39 of relay R, lead 33 and winding of relay R Test relay R severs the stepping circuit at contact 56 stopping both the indicator controller and indicator. The pointer of the latter stands at the designation of the line which is connected to the trunk, informing the'observer what line is under observation.

In addition to rendering the holding magnet of the indicator controller active and closing a gap in the stepping circuit, relay R at contact 45 through lead45 gives a battery connection for the circuit of the parallel relays R and R from the point 14, so that as long as relay R is held energized by relay B through the closure of the 'contact 26 at the observers depressed key K, the triink will be held regardless of the condition of the relays R and R the contacts of which are included in the original energizing path.

After the line lamp Z lighted, the subscribers operator inserted the answering plug of a cord circuit in the jack J, energizing 80 thecut-ofi relay R in the well known manner. The operators relay R receives current in parallel with this, and closing contact 57 provides forthe continued energization of relay R by current through its upper winding after the path through the lower winding has been broken at contact 10 by the release of relay R which is denergized when the cut-off relay opens the circuit of the line relay. The circuit through the upper winding of relay R includes the winding of relay B. This operates and at contacts 58 and 59 closes through the talking leads 60 and 61 of the serviceobserving line to the corresponding trunk conductors L and L so that the observer may listen in. The talking leads having previously been maintained open, clicks and other disturbances produced by the action of the various apparatus associated, inductively or 100 otherwise, with the observing trunk will not get back into the line which -is being observed. The contact 57 also supplies current to the operators signal relay R by way of trunk conductor L winding 62 of 1 the repeating coil, lead 63 and contact 80 of relay R Relay It causes the display of the operators signal Z and the observer thereby knows that the operator has answered. The release ofrelay R would also 1 extinguish thesubscribers signal Z, but thecontrol of this is now transferred. to relay R", the front contact 64 of which supplies current to conductor L The. energizing circuit of relay R is through the winding 7 2 of repeating coil I, lead60, contact 58 of relay R tip side of the line, the substation circuit and the ring side of the line to battery at the cord with which the operator has answered. Having been informed of the 12 number of the line by the indicator, with the indications-furnished by the lamps Z and Z and with her telephone the operator .can follow and record the various details The withdrawal of the plug from the jack J by the subscribers operator in response to the supervisory signal in the cord leads to the deenergization of the cut-off relay and opens the circuit of relay R The latter breaking its contact 57 releases relay R and the operators signal Z ceases to .glow. The

' opening of contact 57 also releases relays R and R The former severe the originating circuit of the relays R and R at contact 11, though these relays are still held up by relay R over lead 45. When the observer frees the key K, it deprives the relays R and R of current by the interruption of their circuit at contact 26 and they break the circuits of relays R and B. These last named relays deenergize the holding magnets H and H and the indicator con; troller and indicator are returned to normal bytheir springs. Belay R falls'ofi when the brush of the indicator controller leaves the contact joined to lead 40. The opening of contact 45 of relay R releases relays R and R, and the latter breaks the circuit of trunk relay R which releases relay R. The observing system is now ready to take up another call.

The call upon the line of the observed group might have been terminating instead of originating. That is, another subscriber may call for a line of the group, andtherefore the first operation in connection with it is the insertion of a calling plug in one of its multiple jacks. Under such conditions the cut-off relay R and the relay R in parallel are first operated. Contact 57 is closed by relay R and relays R and R receive current in series, the former through its upper winding. For a time R remains inert because of the presence of the short circuit 29. As a result of the making of contact 11 of relay R trunk relays R and R are energized, and the display ofthe operators signal Z follows the closure of contact 30 of relay R The opening of contact 28 of relay R removes the short circuit from relay R, which completes the talking leads. This, it will be noted, follows the energization of relays R and B, so thatthe line is protected against, sounds incident to their action and the-operator will be less liable to be made aware that she is being observed. Relay R renders trunk relay R active,

and when the observer throws the key K the various relays of the indicator controller and indicator will be energized and the number of the called line will appear upon the indicator. Relay R responds to the closure of the substation switch hook when the called subscriber answers and operating relay B" lights the subscribers lamp Z at the observing desk. The description of the release of the apparatus for an originating 'call is applicable to the present case.

In either an originating or terminating call, if the observing trunk had already been connected to a line, as L, when the subscriber on line L called or is called, the trunk relay R would be found energized. Therefore, upon the operation of relay R associated with line L, instead of a circuit through back contact 18 for energizing the trunk-seizing relays R and B there would be a circuit through front contact 41 by way of lead 65, resting contact 36 of relay R, conductor 66, resting contact 67 and winding of lock-out rela R resistance r and front contact 19 o relay R Relay R opening contact 67 locks up through contact 68, so that it will remain energized regardless of the condition of the trunk relay. At contact 12 relay R breaks the originating circuit for the trunk seizing relays R and R Consequently the line is locked off the trunk until a new call is made and the trunk is found idle. Since relay R is slow to release, and since its continued energization is through a chain of relays, a sufficient time interval is given so that it will not release if'the subscriber endeavors to attract the attention of the operator by making and breaking the contacts of the switch hook.

The proper maintenance of the lock-out is thus assured.

If two subscribers of the observed group, say upon lines L and L, call simultaneously, the relays R of both the service observing lines associated therewith will operate together, but this relay of line L, which is nearest in the series to the lead 33 and trunk relay R in making contact 39 through which said trunk relay is energized opens contact 35 and this disconnects conductor 34 and the apparatus of line L and all other lines of the group from said relay. Being cut off from the battery connection at the trunk relay, the trunk-seizing relays of line L retract their armatures. It will therefore be seen that the line of the group which is nearest the relay R inthe series through conductors 33 and 34 will always be joined to the trunk in such cases and that there will be no interference.

It may be desired only to observe one class of calls, say those originated by the subscribers upon lines under observation. In such case the key K is closed upon the contact 69. Now when the subscriber upon the line of a group is called and the operator plugs into the jack of the line, this being what has been previously designated as a terminating call, upon the energization of the operators signal relay R as hereinbefore described, there is closed at the front contact a path in parallel with the operators lamp Z through contact 69 of key K, trunk conductor L and winding of observation limiting relay It. Relay R attracts its armature and completes a circuit for the look-out relay R this passing through conductor 38, front contact 37 of relay R, lead 66, resting contact '67 of relay R winding of said relay, resistance 'r" and front contact 19 of relay R Relay R locks itself through contact 68 and opens at .contact 12 the circuit of the trunk-seizing relays R and R. The former at contact 30 cuts off the current from the operators lamp Z before it has time to glow, so the observer receives no signal. At contact 28 relay R applies the short circuit 29 to relay R and this is de'e'nergized, The line is now held locked off the trunk until the call is completed, as in the case of an attempted connection with a busy trunk.

If the call'had instead originated upon the line, the operation proceeds as though the key K were in its central position until the operator in answering inserts the plug in the jack of the calling line. This, provided the observer is occupied with some other line or for any reason fails to take up the call by depressing her key K, operates the relays R and R as just described, and the consequent release of the trunkseizing relays R R and R deenergizes the relays whose circuits are dependent upon them, extinguishing the lamp Z and placing the trunk in a condition to take up another call. But if after seeing the illumination of the subscribers lamp Z and before the operator answers the observer had closed the contacts of the key K, the indicator controller relay B would be operated through key contact 26 and the secondary relay R in turn energized. At its contact 45 the latter closes the holding path for relays R and R from point 1 1 by way of contact 31 of relay R and lead 45. Consequently, when relay R closes its front contact upon the response of the operator and the energization of the operators signal relay R although it operates the lockout relay R this produces no effect because the holding path maintains the trunkseizing relays actuated.

Were terminating calls only to be observed, the key K would be closed upon contact 71. The efi'ect is similar to that just described, in the present instance the observation limiting relay R being operated by the subscribers signal relay R in parallcl with the lamp 1. This causes the relay R to lock-out all originating calls. llpon a terminating call, if. the observer does not depress the key K before the subscriber removes the receiver from its hook in response to the passage of ringing curren over the line following the plugging in with the calling end of a cord circuit by the operator. the attraction of the armature of the subscribers signal relay R will lead to the operation of relay R and the line which seized the trunk will be disconnected therefrom. On the other hand, the closure of contact 26 of key gives the holding path for the trunk-seizing relays through conductor 45 which allows the call to be observed to its completion.

I claim as my invention:

1. The combination with a central station and a service observing station, of a group of' substation lines to be observed terminating at the central station, a trunk connecting the central station and service observing station, and automatic means for connecting to the trunk one at a time the lines put into use.

2. The combination with a central station and a service observing station, of a group of substation lines to be observed terminating at the central station, a trunk connecting the central station and service observing station, and means controlled by conditions produced in the lines for connecting 35 to the trunk one at a time the lines put into use.

3. The combination with a central station and a service observing station, of a group of substation lines to be. observed. terminating at the central station, a trunk connecting the central station and service observing station, and means for connecting a line to the trunk upon the initiation of a call upon the line by a subscriber or the connection with said line by an operator.

4. The combination With'a central station and a service observing station, of a group of substation lines to be observed terminating at the central station, a trunk con- 10o necting the central station and service observing station, means for connecting to the trunk a line put into use, andmeans for preventing other lines of the group from obtaining access to the trunk while the first line is connected thereto.

5. The combination with a central station and a service observing station, of a group of substation lines to be observedterminating at the central station, a trunk connecting the central station and service observing station, means controlled by conditions produced in the lines for connecting to the trunk a line put into use, and means responsive to the connection for preventing other lines of the group from obtaining access to the trunk while the first line is connected thereto.

6. The combination with a central station and a service observing station, of a group 126 of substation lines to -be observed terminating at the central station, a. trunk connect- -g tb' central station and service observing station, and relays for connect-ing to the trunk one at a time the lines put into use.

7. The combination with a central station and a service observing station, of a group of substation lines to be observed terminating at the central station, a trunk connecting the central station and service observing 130 each line of the group station, and automatic means for connecting to the trunk one at a time the lines put into use and consisting of relays individual to each line of the group and relays common to the group. 4

8. The combination with a central station and a service observing station, of a group of substation lines to be observed terminating at the central station, a trunk connecting the central station and service observing station, and automatic means for connecting to the trunk one at a time the lines put into use and consisting of relays individual to and relays common to the group and associated with the trunk.

9. In a service-observing system, a subscribers operators position, a group of lines to be observed each terminating at said position, an observing station, a trunk for connecting said positlon and station, a trunkseizing relay associated with each line, a trunk relay common to the group of lines and energized by the trunk-seizing relay,

and a relay controlled by the trunk relay for preventing the seizure of the trunk.

10. In a service-observing system, a subscribers operators position, a group of lines to be observed each terminating at said po-' sition, an observing station, a trunk r'or connecting said position and station, a trunkseizing relay associated with each line, a trunk relay common to the group of. lines and energized by the trunk-seizing relay, and a relay controlled by the trunk relay for opening thecircuit of the trunk-seizing relay.

11. In a service observing system, a group of lines to be observed, a trunk, a trunk-seizing relay associated with each line, a lockout relay for preventing the seizure of the trunk, and a manually controlled relay common to the group of lines for controlling both the trunk-seizing relay and the lockout relay.

12. In a service observing system, a group of lines to be observed, a trunk, a trunkseizing relay associated with each line, a lock-out relay for preventing the seizure of the trunk, and a relay common to the group of lines for controlling the trunk-seizing relay at its back contact and the lock-out relay at its front contact.

13. A service-observing station, a serviceobservin trunk terminating at the station, a su-bscri ers operators position adapted to be connected to said trunk, a line to be observed terminating at said position, there bein talking conductors and controlling cons uctors belonging to the line and trunk, and means dependent-upon the putting of the line into use for connecting the controlling conductors of the line and trunk and thereafteinconnecting the talking conductors.

14. A service-observing station, a serviceobserving trunk terminating at the station, a subscribers operators position adapted to be connected to said trunk, a line to be observed, a plurality of trunk-seizing devices adapted to successively perform steps in connecting the line and trunk and associated with the line, and a plurality of means for operating said devices at different times.

15. A service observing trunk, a line to be observed, a plurality of trunk-seizing relays individual to the line, means for energizing a plurality of relays simultaneously, and means for thereafter energizing another of said relays.

16. A service observing trunk, a line to be observed, a plurality of trunk-seizing relays individual to the line, means for energizing one of said relays, and 'aeans dependent upon the operation of said relay for energizing another of the relays.

17. A service observing trunk, a line to be observed, there being talking conductors and controlling conductors belonging to the line and trunk, a plurality of trunk-seizing relays associated with the line, means dependent upon the putting of the line into use for energizing a relay to connect con-- trolling conductors of the line and trunk, and means governed by said energized relay for causing the, energization of another relay to connect the talking conductors.

18. The combination with a line the service of which is to be observed, of a service observing system comprising observation controlling electro-mechanisms, service observing trunk conductors connecting the line and observing system,- conductors for uniting the electro-mechanisms with one another and with the trunk conductors and line, and meansrassociated with the conductors for preventing disturbances from being communicated therethrough to the observed line.

19. The combination with a line the service of which is to be observed, of a service observing system comprising observation controlling electro-mechanisms, service observing trunk conductors connecting the line and observing system, conductors for uniting the eleetro-mechanism with one another and with the trunk conductors andline, and means associated with the trunk conductors for preventing disturbances from being communicated therethrough t0 the observed line.

20. The combination with a line the service of which is to he observed, of a service observing system comprising observation controlling electro-mechanisms, service observing trunk conductors connecting the line and observing system, conductors for uniting the 'electro-mechanisms with one another and with the trunk conductors and line, and means for interrupting the conductive continuity of the conductors whereto the observed line.

21. In a service observing system, a group of lines to be observed, an observing trunk, electro-mechanisms for connecting any one of the lines to the trunk for observation and for enabling such observation to be made, and means for preventing sounds from being applied to the line through the service observing instrumentalities.

22. In a service. observing system, a group of lines to be observed, an observing trunk, electro-mechanisms for connecting any one of the lines to the trunk for observation and for .enabling such observation to be made, and means for preventing sounds pro duced in the operation of the electro-mechanisms from being applied to the line.

28. In a service observing system, an observing station, a group of lines to be observed, a trunk extending from the observing station to the group of lines, means operable as'the lines are put into use upon the initiation of a call upon a line by a subscriber or by the connection with said line by an operator for connecting them to the trunk for observation, and means for preventing the simu'ltaneous connection of lines to the trunk.

24;. In a service observing system, an observing station, a group of lines to be observed, a trunk extending from the observing station to the grou of lines, electroresponsive means operab e to eflect the connection of a line with the trunk, and a circuit for said means extending through the equipment of a plurality of lines, said circuit being opened at said means upon the connection of the trunk with one of the lines of the group; I 25. In a service observing system, an observing station, a group of lines to be observed, a trunk extending from the observing station to the group of lines, electroresponsive means associated with each line of the group for connecting it with the trunk, and a circuit for said means extending through the apparatus of a plurality of lines of the group, said circuit being opened at said means upon, the connection with the trunk of one of the lines of the group.

26. In a service observing system, an observing station, a group of lines to be observed, a trunk extending from the observing station to the group of lines," electroresponsive means associated with each line of the group for connecting it with the trunk, and a locking circuit for said means extending through the apparatus of a plurality of lines of the group, saidcircuit being opened upon the connection with the trunk of one of the lines of the group.

27. In a service observing system, an 0bserving station, a group of lines to be observed, a trunk extending from the observing station to the group of lines, electro-responsive means associated with each line of the group and with the trunk for connecting such line with the trunk, and a circuit for said means extending through the apparatus of a plurality of lines of the group, said circuit bein opened upon the connection with the trun of one of the lines of the group.

28. In a service observin system, an observing station, a group 0 lines' to be observed, a trunk extending from the observing station to the group of lines, a trunkseizing relay associated with each line, a trunk relay common to the group of lines and governing the operation of the trunkseizing relay, and an energizing'circuit for the trunk relay extending through contacts belonging to the trunk-seizing relays of a plurality of lines of the group.

29. In a service observ1n system, an observing station, a group 0? lines to be observed, a trunkextending from the observing station to the group of lines, a trunkseizing relay associated with each line, a trunk relay common to the group of lines and governing the operation of the trunkseizing relay, and an energizing circuit for the trunk relay and a locking circuit for the trunk-seizing relays controlled by a plurality of the trunk-seizing relays.

30. In a service observing system, a plurality of substation lines to be observed and their individual equipment, a service observing line adapted for temporary'association with each substation line to be observed and having apparatus under the control of the substation line equipment, a,-se1*v,icc 0bserving station provided with service, observing apparatus, and a trunk multipled to the service observing lines and connected to the service observing apparatus at the observing station.

31. In a service observin system, a plurality of substation lines 110%)8 observed and their individual equipment, a service ob serving line adapted for temporary association with each substation line to be observed and having apparatus under the control of the substation line equipment, a service observing station provided with service observing apparatus, a trunk multipled to the service observing lines and connected to the service observing apparatus at the observing station, and apparatus in the trunk cooperating with that of the service observing lines in the control of the service observing apparatus.

32. In a service observing system, a plurality of substation lines to be observed and their individual equipment, a service observing line adapted for temporary association with each substation line to be observed and having apparatus under the control of the substation line equipment, a service observprovided with service observing a trunk multipled to the service observing lines and connected to the service observing apparatus at the observing station, and apparatus in the trunk cooperating with that of the service observing station in the control of the service observing apparatus.

33. In a service observin system, aplurality of substation lines to be observed and their individual equipment, a service observing line adapted for temporary association with each substation line to be .observed and having apparatus under the control of the substation line equipment, a service observing station provided with service observing apparatus, a trunk multipled to the service observing lines and connected to ing station apparatus,

the service observing apparatus at the observing station, and apparatus in the trunk' cooperating with that of the service observing lines and of the service observing station in the control of the service observing apparatus,

34. In combination, a subscribers operators position, a group of lines terminating in said position, a service-observing station, a trunk for connecting said position and the service-observing station, automatic means responding to acts of the subscriber and the operator for connecting the lines to the trunk one at a time as they are put I into use, and a signal at the observing station dependent in its operation-upon the condition of the connected line.

35. In combination, a subscribers operators position, a group of lines terminating in said position, a service-observing station, a trunk for connecting said position and the service-observing station, automatic means responding to acts of the subscriber and the operator for connecting the lines to the trunk one at a time as they are put into use, and a' signal at the observing station dependent in its operation upon connection with the line by an operator. 1

36. The combination with a group of telephone lines extending from substations to a central station, of a service observing station, a trunk terminating at the service observing station, automatic means for connecting the lines to the trunk one at a time as they are put into use, and a signal at the observing station dependent in its operation upon the condition of the line at the substation.

37. The combination with a group of telephone lines extending from substations to a central station, of a service observing station, a trunk terminating at the service observing station, automatic means for connecting the lines to the trunk one at a time as they are put into use, and signals at the observing station dependent in their operation upon the condition of a line at the sub- 39. The combination with a group of telephone lines extending from substations to a central station and each having a line relay, of a service observing station, a trunk terminating at the. service observing station, automatic means for connecting the trunk to a line of the group to be observed, a signal relay joined to the trunk at the observing station, a signal controlled thereby, and a relay governed by the line relay and governing the connecting means and signal relay.

40. Thecombination with a group of telephone lies extending from substations to a central station and each having a cut-off relay, of a service observing station, a trunk terminating at the service observing station, automatic means for connecting. the trunk to a line of the group to be observed, a signal relay joined to the trunk at the observing station, a signal controlled thereby, and a relay governed with the cut-off relay and governing the connecting means and signal relay.

41. The combinationwith a group of telephone lines extending from substations to a central station, of a service observing station, a trunk terminating at the service observing station, automatic means for connecting the trunk to a line of the group to be observed, a signal at the observing station, and an electro-mechanism situated at'the central station and being common to the group of lines, said electro-mechanism being responsive to the condition of the line to control the signal.

42. The combination with a group of telephone lines extending from substations to a central station and each having a line relay, of a service observing station, a trunk terminating at the service observing station, automatic means for connecting the trunk to a line of the group to be observed, a signal relay joined to the trunk at the observing station, a signal controlled thereby,

observing station, a relay for connecting the line to the-trunk, a signal relay joined to the trunk at the observing station, a signal controlled thereby, and a relay governed by the line relay and governing the signal relay.

4:4. The combination with a telephone line having a cut-off relay, of a service observing station, a trunk terminating at the service observing station, a relay for connecting the line to the trunk, a signal relay joined to the trunk at the observing station, a signal controlled thereby, and a relay operable with the cutofi' relay and governing the signal relay.

45. The combination with a telephone line having a line relay and a cut-off relay, of a service observing station, a trunk terminating at the service observing station, a relay for connecting the line to the trunk, signal relays joined to the trunk at the observing station, signals controlled thereby, and relays operable with the line and cut-0E relays and governing the signal relays.

46. A service observing station, lines to be observed, connections between the lines and observing station, a plurality of signals at the observirs' station respectively responsive to different line conditions, and means under the control of the station observer for limiting the operation to one class of line conditions.

47. A service observing .station, lines to be observed, connections between the lines and observing station, a plurality of signals at the observing station respectively resnonsive to difierent line conditions, and mi'ans under the control of the station observer including a device normally acting to display a signal for limiting the operation to one class of line conditions.

48. A service observing station, lines to be observed, connections between the lines and observing station, a subscribers signal and an operators signal at the observing station, relays under the influence of difi'erent line conditions for respectively controlling the signals, a key, and a relay controlled by said key for rendering the signal relays inef-- festive.

49. A service observing station, lines to be observed, connections between the lines and observing station, a subscribers signal and an operators signal at the observing station, relays under the influence of difierent line conditions for respectively controlling the signals, a key, and a relay controlled by said key and by the signal relays for rendering said signal relays ineffective.

58. A service observing station, lines to be observed, a trunk terminating at the observing station, trunk-seizing means for connecting each line to the trunk, lock-out means for preventing the trunk-seizing means from making a connection, a plurality of signals at the observing station respectively responsive to different line conditions, manual controlling means therefor, and means operable upon the actuation of the controlling means for governing the lock-out means.

51. A service observing station, lines to be observed, a trunk terminating at the observing station, trunk-seizing means for connecting each line to the trunk, lock-out means for preventing the trunk-seizing means from making a connection, a plurality of signals at the observing station respectively responsive to different line conditions, manual controlling means therefor, andobservation limiting means operable upon the actuation of the controlling means for governing the look-out means.

52. A service observing station, lines to be observed, a trunk terminating at the observing station, trunk-seizing means for connecting each line to the trunk, lock-out means for preventing the trunk-seizing means from making a connection, and means controlled by the observer for rendering the look-out means ineffective.

53. A service observing station, lines to be observed, a trunk terminating at the observing station, trunk-seizing means for connecting each line to the trunk, lock-out means for preventing the trunk-seizing means from making a connection, and means including contacts of an observers key for rendering the look-out means inefi'ective.

54. A service observing station, lines to be observed, a trunk terminating at the observingstation, a trunk-seizing relay for con necting each line to the trunk, a lock-out relay energized to prevent the operation of the trunk-seizing relay, an operating circuit for the trimk-seizing relay extending through normal contacts of the look-out relay, and a branch circuit for completing said operating circuit independently of the lock-out relay.

55. A service observing station, lines to be observed, a trunk terminating at the observing station, a trunk-seizing relay for connecting each line to the trunk, a lock-out relay energized to prevent the operation of the trunk-seizing relay, an operating circuit for the trunk-seizing relay extending through normal contacts of the lock-out relay, a branch circuit for completing said operat ing circuit independently of the look-out relay, and an observers key for controlling said branch circuit.

56. A service observing station, a trunk terminating thereat, a group of lines to be observed, automatic means for connecting any one of the lines to the trunk, automatic means controlled in the operation of the connecting means for indicating which of the lines is thus connected, and a manual device at the observing station for initiating the operation of said indicating means.

A. Service observing station, a trunk "to a point determined terminating thereat, a group of lines, any one of which may be connected to the trunk for observation, -a line indicator at the observing station, an indicator controller at the other extremity of the trunk, means op erable in the connection of a line to the trunk to govern the indicator controller, said indicator controller governing the indicator, and a key-controlled energizing circuit including both indicator and controller.

58. A service observing station, a trunk terminating thereat,,a group of lines to be observed,-means for connecting any one of the lines to the trunk, a controlling electromechanism associated with the lines at one extremity of the trunk and being movable by the line connected therewith, and an indicating electro-mechanism situated at the observing end of the trunk and controlled in its movement by the first named electro-mechanism.

59. A service observing station, a trunk terminating thereat, a group of lines to be observed, means for connecting any one of the lines to the trunk, a controlling electromechanism associated with the lines at one extremity ofthe trunk and being movable to a point determined by the line connected therewith, and an indicating electro-mechanism situated at the observing end of the trunk and movable in synchronism with the first named electro-mechanism.

60. A service observing station, a trunk terminating thereat, a group of lines to be observed, means for connecting any one of the lines to the trunk, a controlling electromechanism associated with the'lines at one extremity of the trunk and being movable to a point determined by the line connected therewith, an indicating electro-mechanism situated at the observing end of the trunk and movable in synchronism with the first named eiectro-mechanism, an observers key, and an energizing circuit for the electromechanisms passing through contacts of the observers key.

61. A service observing station, a trunk terminating thereat, a group of lines to be observed, means for connecting any one of the iines to the trunk, a controlling electromechanism associated with the lines at one extremity of the trunkand being movable to a point determined by the line connected therewith, an indicating electro-mechanism situated at the observing end of the trunk and movable in 'synchronism with the first named electro-'mechanism, an observer s' key, and a circuit preparing the electro-mechanisms for operation passing through contacts of the key.

62. In a service observing system, a central station at which is a subscribers operators position, a group of substation lines terminating at said position, a service observingline'adapted for temporary association with each substation line to be observed, a service observing station, a service observing trunk, automatic means at the central station for connecting any one of the service observing lines to the trunk, and automatic means associated with the trunk at the service observing station for indicating which of the lines is thus connected.

63. In a service observing system, a central station at which is a subscribers operators position, a group of substation lines terminating at said position, a service observing station, a service observing trunk, automatic means at the central station for connecting any one of the substation lines through said trunk to the service observing station, and automatic means associated with the trunk at the service observing station for indicating which of the lines is thus connected.

64:. In a service observing system, a central station at which is a subscribers operators position, a group of substation lines terminating at said position, a service observing station, a service observing trunk, means at the central station for connecting any one of the substation lines through said trunk to the service observing station, and automatic means associated with the trunk at the service observing station for indicating which of the lines is thus connected.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses, this seventeenth day of November, 1915.

EDWARD G. MQLINA.

Witnesses:

WILLIAM r1. I-In'annn, 

